Enterprise Products Partners L.P. provides midstream energy services to producers and consumers of natural gas, natural gas liquids (NGLs), crude oil, petrochemicals, and refined products. It operates in four segments: NGL Pipelines & Services, Crude Oil Pipelines & Services, Natural Gas Pipelines & Services, and Petrochemical & Refined Products Services. The NGL Pipelines & Services segment offers natural gas processing and related NGL marketing services. It operates natural gas processing facilities located in Colorado, Louisiana, Mississippi, New Mexico, Texas, and Wyoming; NGL pipelines; NGL fractionation facilities; NGL and related product storage facilities; and NGL marine terminals. The Crude Oil Pipelines & Services segment operates crude oil pipelines; and crude oil storage and marine terminals, which include a fleet of approximately 250 tractor-trailer tank trucks that are used to transport crude oil. It also engages in crude oil marketing activities. The Natural Gas Pipelines & Services segment operates natural gas pipeline systems to gather, treat, and transport natural gas. It leases underground salt dome natural gas storage facilities in Napoleonville, Louisiana; owns an underground salt dome storage cavern in Wharton County, Texas; and markets natural gas. The Petrochemical & Refined Products Services segment operates propylene fractionation facilities, including propylene fractionation units and propane dehydrogenation facilities, and related marketing activities; butane isomerization complex and related deisobutanizer operations; and octane enhancement, isobutane dehydrogenation, and high purity isobutylene production facilities. It also operates refined products pipelines and terminals; and ethylene export terminals; and provides refined products marketing and marine transportation services. Enterprise Products Partners L.P. was founded in 1968 and is headquartered in Houston, Texas.

Kinder Morgan, Inc. operates as an energy infrastructure company primarily in North America. The company operates through Natural Gas Pipelines, Products Pipelines, Terminals, and CO2 segments. The Natural Gas Pipelines segment owns and operates interstate and intrastate natural gas pipeline, and storage systems; natural gas gathering systems and natural gas processing and treating facilities; natural gas liquids fractionation facilities and transportation systems; and liquefied natural gas gasification, liquefaction, and storage facilities. The Products Pipelines segment owns and operates refined petroleum products, and crude oil and condensate pipelines; and associated product terminals and petroleum pipeline transmix facilities. The Terminals segment owns and/or operates liquids and bulk terminals that stores and handles various commodities, including gasoline, diesel fuel, renewable fuel and feedstocks, chemicals, ethanol, metals, and petroleum coke; and owns tankers. The CO2 segment produces, transports, and markets CO2 to recovery and production crude oil from mature oil fields; owns interests in/or operates oil fields and gasoline processing plants; and operates a crude oil pipeline system in West Texas, as well as owns and operates RNG and LNG facilities. It owns and operates approximately 82,000 miles of pipelines and 139 terminals. The company was formerly known as Kinder Morgan Holdco LLC and changed its name to Kinder Morgan, Inc. in February 2011. Kinder Morgan, Inc. was founded in 1997 and is headquartered in Houston, Texas.

ONEOK, Inc. engages in gathering, processing, fractionation, storage, transportation, and marketing of natural gas and natural gas liquids (NGL) in the United States. It operates through four segments: Natural Gas Gathering and Processing, Natural Gas Liquids, Natural Gas Pipelines, and Refined Products and Crude. The company owns natural gas gathering pipelines and processing plants in the Mid-Continent and Rocky Mountain regions; and provides midstream services to producers of NGLs. It also owns NGL gathering and distribution pipelines in Oklahoma, Kansas, Texas, New Mexico, Montana, North Dakota, Wyoming, and Colorado; terminal and storage facilities in Kansas, Nebraska, Iowa, and Illinois; NGL distribution pipelines in Kansas, Nebraska, Iowa, Illinois, and Indiana; transports refined petroleum products, including unleaded gasoline and diesel; and owns and operates truck- and rail-loading, and -unloading facilities connected to NGL fractionation, storage, and pipeline assets. In addition, the company transports and stores natural gas through regulated interstate and intrastate natural gas transmission pipelines, and natural gas storage facilities. Further, it owns and operates a parking garage in downtown Tulsa, Oklahoma; and leases excess office space and rail cars. Additionally, the company transports, stores, and distributes refined products, NGLs, and crude oil, as well as conducts commodity-related activities, including liquids blending and marketing activities. It serves integrated and independent exploration and production companies; other NGL and natural gas gathering and processing companies; crude oil and natural gas production companies; utilities; industrial companies; natural gasoline distributors; propane distributors; municipalities; ethanol producers; petrochemical, refining, and marketing companies; and heating fuel users, refineries, and exporters. ONEOK, Inc. was founded in 1906 and is headquartered in Tulsa, Oklahoma.

Targa Resources Corp., together with its subsidiary, Targa Resources Partners LP, owns, operates, acquires, and develops a portfolio of complementary domestic midstream infrastructure assets in North America. It operates in two segments, Gathering and Processing, and Logistics and Transportation. The company is involved in gathering, compressing, treating, processing, transporting, and selling natural gas; storing, fractionating, treating, transporting, and selling natural gas liquids (NGL) and NGL products, including services to liquefied petroleum gas exporters; and gathering, storing, terminaling, purchasing, and selling crude oil. It is also involved in the purchase and resale of NGL products; and sale of propane, as well as provision of related logistics services to multi-state retailers, independent retailers, and other end-users. In addition, the company offers NGL balancing services; and transportation services to refineries and petrochemical companies in the Gulf Coast area, as well as purchases, markets, and resells natural gas. As of December 31, 2023, it leased and managed approximately 605 railcars; 137 tractors; and 6 vacuum trucks and 2 pressurized NGL barges. Targa Resources Corp. was incorporated in 2005 and is headquartered in Houston, Texas.

Plains GP Holdings, L.P., through its subsidiary, Plains All American Pipeline, L.P., owns and operates midstream infrastructure systems in the United States and Canada. It operates in two segments, Crude Oil and Natural Gas Liquids (NGLs). The company engages in the gathering and transporting crude oil and NGLs using pipelines, gathering systems, and trucks. It engages in the loading and unloading services at terminals; NGL fractionation and isomerization services; and natural gas and condensate processing services. The company offers logistics services to producers, refiners, and other customers. PAA GP Holdings LLC operates as a general partner of the company. Plains GP Holdings, L.P. was incorporated in 2013 and is headquartered in Houston, Texas.

NGL Energy Partners LP engages in the transportation, storage, blending, and marketing of crude oil, natural gas liquids, refined products/renewables, and water solutions. The company operates through three segments: Water Solutions, Crude Oil Logistics, and Liquids Logistics. The Water Solutions segment transports, treats, recycles, and disposes produced and flowback water generated from crude oil and natural gas production; aggregates and sells recovered crude oil; disposes solids, such as tank bottoms, and drilling fluid and muds, as well as performs truck and frac tank washouts; and sells produced water for reuse and recycle, and brackish non-potable water. The Crude Oil Logistics segment purchases crude oil from producers and marketers, and transports it to refineries for resale at pipeline injection stations, storage terminals, barge loading facilities, rail facilities, refineries, and other trade hubs; and provides storage, terminaling, and transportation services through pipelines and storage tanks. The Liquids Logistics segment supplies natural gas liquids, refined petroleum products, and biodiesel to commercial, retail, and industrial customers in the United States and Canada through its 23 terminals, third-party storage and terminal facilities, and nine common carrier pipelines, as well as through a fleet of leased railcars. This segment also provides services for marine exports of butane through its facility located in Chesapeake, Virginia; and owns a propane pipeline in Michigan. NGL Energy Holdings LLC serves as the general partner of the company. The company was founded in 1940 and is headquartered in Tulsa, Oklahoma.

Adams Resources & Energy, Inc., through its subsidiaries, primarily engages in the marketing, transportation, terminalling, and storage of crude oil and other related products in the United States. The company operates through four segments: Crude Oil Marketing, Transportation, Pipeline and Storage, and Logistics and Repurposing. It purchases and sells crude oil to refiners and other customers primarily onshore in Texas, North Dakota, Michigan, Wyoming, Colorado, and Louisiana; owns and operates a fleet of 164 tractor-trailer rigs; and maintains pipeline inventory locations and injection stations. The company also transports liquid chemicals, pressurized gases, asphalt, and dry bulk on a hire basis in the United States, Canada, and Mexico; and operates truck terminals in Houston, Corpus Christi, Nederland, Freeport, Baton Rouge, St. Rose, Sterlington, Jacksonville, Tampa, Augusta, Mobile, Charlotte, Cincinnati, South Charleston, Memphis, East St. Louis, and Joliet. In addition, it operates crude oil and condensate pipeline system, which connects the Eagle Ford Basin to the Gulf Coast waterborne market; and transports crude oil, condensate, fuels, oils, and other petroleum products on a for hire basis in the Eagle Ford basin. The company was founded in 1947 and is headquartered in Houston, Texas.

NuStar Energy L.P. engages in the transportation, terminalling, and storage of petroleum products and renewable fuels, and transportation of anhydrous ammonia in the United States and internationally. It operates through three segments: Pipeline, Storage, and Fuels Marketing. The Pipeline segment engages in the transportation of refined products, crude oil, and anhydrous ammonia. The Storage segment offers storage, handling, and other services for refined products, crude oil, specialty chemicals, renewable fuels, and other liquids. The Fuels Marketing segment provides bunkering operations in the Gulf Coast; and blending operations with Central East System primarily for ship owners, marketers, and traders. The company was incorporated in 1999 and is headquartered in San Antonio, Texas.